According to the World Health Organization, a trace amount of methanol is common in fermented drinks. However, higher concentrations — such as when methanol is added deliberately to alcohol — can be deadly.

Symptoms of methanol poisoning may not appear immediately. They include acute abdominal pain, acute headache and ataxia (lack of coordination of body movements), according to the Health Ministry.

“After a variable period of time, victims start to develop headache, vomiting, abdominal pain and vertigo. They may start to hyperventilate and feel breathless,” WHO says.

Editor’s note: A previous version of this story featured a different lead photo for illustrative purposes.